CMS Save hangs

Hi, I am a total newbie to SilverStripe and many of the relevant technologies so please bear with my relative lack of knowledge.

After successfully installing SilverStripe and entering the CMS using the admin login, I tried to make a few changes to things like site name etc. When I hit save or save and publish for any page though, the save button keeps rotating and nothing ever happens - no errors, saving just never finishes. I know that this is an issue that has been raised before but the posts I have found are from a long time ago and this looks like it might be a different problem.

From firebug, I get: initialiseForm is not defined, Line 645
IE gives an error on page message along the lines of expected object: /admin at the same place

Can anyone shed any light or help me get to the root of this? I'd be really grateful!